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Planning & Research >  Spans of Time >  Historic >  Modified Pratt Through Truss Contact Planning & Research

Table of Contents

List of Figures

Acknowledgements

Introduction

History of Oklahoma Highway Bridges

The Historic Bridges of Oklahoma
Steel Truss Bridges
• King Post Pony
• Small Pratt (3 panel) Pony
• Truss Leg Bedstead Pony
• Pratt Pony
• Pratt Half-Hip Pony
• Parker Pony
• Camel Back Pony
• Warren w/ Verticals Pony
• Warren w/ Polygonal Top Chord Pony
• Warren Bedstead Pony
• Double Intersection Warren Pony
• Pratt Through
• Modified Pratt Through
• Parker Through
• Camelback Through
• Modified Parker Through
• Warren Through
• K-Truss
• Deck Truss
• Mixed Truss

Concrete and Stone Bridges
• Concrete Arch
• Rainbow Arch
• Stone Arch

Endnotes

Bibliography

Appendices




MODIFIED PRATT THROUGH TRUSS

    1921	Bryan		07E2080N3830005	  General Const.
			


  The development of standard designs by engineers within the state haghway department led to modifying the parallel chord Pratt through truss for use on principal highways with heavier and faster traffic.  The modifications involved subdividing the panels to give the structure greater strength and support.  These technical changes related directly to the increasing number of automobiles and trucks, the latter vehicles in Oklahoma often transportating heavy oilfield rigs and equipment.  For the main state road between Bokchito nad Durant in Bryan County, highway department engineers in 1921 specified the modified Pratt, the project going to the General Construction Company of St. Louis (Figure 61).  The firm, too, illustrates a trend of the 1920s.  During those years the old-line, traditional bridge companies lost ground to general contractors who took on bigger projects from the state, sometimes constructing the road while simply purchasing the spans from bridge fabricators or subcontracting that part of the job.


Bridge 07E2080N3830005 is modified Pratt through truss that spans Caddo Creek, three miles east of Bokchito in Bryan County.
Figure 61.  Bridge 07E2080N3830005 is modified Pratt through truss that spans Caddo Creek, three miles east of Bokchito in Bryan County.



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